A model of resisting the moral hazard in the medical insurance field is set up based on the incentive theory,and the different incentive mechanisms of the model are discussed in three different conditions,namely the complete information condition,the incomplete information condition with the(agent's) risk neutrality and the incomplete information condition with the (agent's) risk aversion.In the three different conditions,the incentive mechanisms take effect in different levels.Particularly,the(agent) would get more information rent in the incomplete information condition with the agent's risk aversion.